Patent GB-1444122-A (GB)
Title: Production of activated carbon precursors
IPC: C01B31/08
Filed: 1973-09-14
Abstract: 1444122 Activated carbon and precursors MARUZEN OIL CO Ltd 14 Sept 1973 [14 Sept 1972] 43387/73 Heading C1A An infusible carbonized starting material useful in the production of activated carbon is made by reacting a heavy petroleum material and a sulphonating agent in the presence of a liquid reaction medium, whereby the heavy petroleum material is converted into the said infusible carbonized material, which material is not softened by an activation treatment. Specified heavy petroleum materials include asphalt, catalytic decomposition residues of heavy oil or kerosene, thermal decomposition residues of kerosene or light oil, naphtha decomposition residues, residues obtained in the coking, thermal decomposition, gasifying, or hydrocracking of a heavy fraction or a residual oil, petroleum pitch or petroleum coke. Coal or charcoal may be added to the heavy petroleum material. Sulphonating agents specified, which may be present in an amount of 0À2 to 20 times by weight the amount of heavy petroleum material include fuming and concentrated sulphuric acid, sulphur trioxide, chloro-sulphonic acid, a complex salt of sulphur trioxide and a basic compound, a complex salt of chlorosulphonic acid and a weakly basic material, fluorosulphonic acid, sulphoallyl chloride, sulphamic acid, an acyl sulphate or an alkyl sulphate. Thus complex salts of sulphur trioxide and pyridine, dioxane, trimethylamine, dimethylaniline, thioxane, bis - (2 - chloroethyl)- ether, 2-methylpyridine, quinoline, dimethyl formamide and triethyl phosphate, and complex salts of chlorosulphonic acid and diethyl ether, dioxane and dimethyl formamide may be used. An oxidizing agent, e.g. potassium permanganate or nitric acid, may be added to the sulphonating agent. The reaction medium which may be present in 0À2 to 30 times by weight the amount of the heavy petroleum material, may be one or more halogenated lower aliphatic compounds, e.g. dichloromethane, 1,1,2-trichloroethane, 1,1,2,2 - tetrachloroethane, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, perchloroethylene, 1,1,1,2-tetrachloroethane, pentachloroethylene and mixtures thereof. Dimethyl formamide, dioxane, acetic acid and benzene may also be used. The reaction may be conducted at 0‹ to 300‹ C., especially 50‹ to 150‹ C., for from 30 minutes to 10 hours, especially 1 to 5 hours. Desirably, the heavy petroleum material and sulphonating agent are reacted until the softening point of the carbonized material is greater than 700‹ C. especially greater than 900‹ C. After the reaction the reaction medium may be distilled off and the carbonized material filtered off, or further heated to 150‹ to 300‹ C. to decompose remaining sulphonating agent. Activated carbon is made from the carbonized product by steam activation in a fluidized or fixed bed at 800‹ to 900‹ C. for ¢ to 3 hours with steam in an amount of 1 to 20 times by weight the amount of the starting material fed. Alternatively zinc activation may be used, the starting material being treated with 1 to 10 times its weight of an activating agent comprising water, zinc chloride, and concentrated hydrochloric acid at 600‹ to 700‹ C. for ¢ to 3 hours. Activated carbon so made is of granular form; in a typical example granules have a major axis of 4 mm., a minor axis of 3 mm and a thickness of about 1 mm., with a specific surface area of 1700 m.<SP>2</SP>/g., a methylene blue-adsorptive power of 430 mg./g., and a bulk density of 0À398 g./c.c.